Concentration of ores.



. the specification of UNITED STATES PATENT OFFICE.

ARTHUR HOWARD HIGGINS, OF LONDON, ENGLAND, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 MINERALS SEPARATION NORTH AMERICAN CORPORATION.

No Drawing.

To all whom it may concern:

Be it known that I, ARTHUR HOWARD HIGGINS, a subject of the King of England, residing at 62 London vVall, London, England, have invented certain new and useful Improvements in the Concentration of Ores.

This invention is for improvements in or relating to the concentration of ores and especially to preferential or selective flotation, that is to say, to the separation of different metallic sulfids from one another as Well as from gangue when flotation processes are used, and the present invention is in some respects a development from that described in the prior United States Patent to Nutter 625 at, No. 1067485, issued July 15, 1913.

For the purpose of defining the nature of this invention it is desirable first to discuss the factors which obtain in froth flotation processes and for this purpose attention will be particularly directed to the ap paratus'of the sub-aerator type defined in my United States Patent No. 1,155,816, issued October 5,1915, that is to say, to a flotation apparatus in which the particles in the pulp in a comparatively quiet zone in the upper portion of the flotation vessel are subjected to the action of a continuous stream of innumerable minute gaseous bubbles rising to a froth outlet at the top.

important factor in froth flotation processes is the tendency of a particle to be wetted by water, and conversely the tend ency of a particle to become dry or to be come attached to a gaseous bubble. The gangue particles have the greatest tendency to be wetted by water and have the least tendency to be attached to gaseous bubbles. Further, comparing galena and blende, for example, the particles of galena appear to have the least tendency to be wetted by Water or the greatest tendency to become attached to gaseous bubbles, while blende particles appear to have a somewhat smaller tendency to be attached to gaseous bubbles. yrites appear to have a still greater tendency than galena to be attached-to gaseous bubbles. p

In a flotation process (particularly if carried out in an referred to) it Specification of Letters Patent.

apparatus of the type above is found that another im-- Patented Aug. 14,1917.

Application filed September 23, 1914. Serial No. 863,098.

portant factor is the rate at which the different particles fall in water or the weight of the particles in Water in relation to their size.

If a pulp contains very fine particles of blende and galena of the same size, the galena particles will be heavier than the blende particles in the relation of about 7 to 4 or their weight in water will be in the relation of about 6 to 3. The galena particles will therefore have a much greater rate of fall in water than the blende particles.

If such a sized product is subjected to a flotation process under conditions suitable for preferential flotation, it is found that the gravity factor predominates and the zinc is floated more readily than the lead.

This invention, therefore, lies in a process for the selective separation of the difl'erent constituents of anore by flotation in which the finely crushed ore is sized so as to yield products containing particles of substantially uniform size, whereupon these products are separately treated by a preferential flotation process so products relatively high in a certain sulfid on the one hand and residues relatively high in another sulfid on the other hand.

In the original agitationv froth apparatus as illustrated in the prior United States Patent to Sulman et at, N 0. 835120, issued November 6, 1906, for example, the actual formation of the froth took place on the surface of a spitzkasten in which the liquid was comparatively at rest, and the gravity factor played little or no part.

ration does not take placein a spitzkasten, but Where the separation of the froth takes place at the top of the agitation and aeration vessel itself, the phenomenon of gaseous flotation is a dynamic one and the gravity factor may be caused to play a considerable part.

Briefly it-may be stated that this invention consists in the simultaneous use of the factors of difl erential gaseous attachment 100 and differential falling secure selective flotation.

In carrying this invention into effect it power in liquid to isfound that the. conditions most suitable for preferential or selective flotation are as 105 follows as to obtain flotation In the subaerator type of apparatus where the sepa-' The frothing agent employed should be partly soluble in water, such as eucalyptus amygdalina, and the proportion employed should be very small (about one or two ounces per ton of ore treated, 71. e. for four tons of water). Additions of frothing agent may be made during the treatment if it is desired to increase the rate at which the froth is produced, care being taken to avoid excess. In a number of previous patents relating to this subject reference has been made to the use of solutes such as acids, alkalis, and soluble salts to assist the selection of the air bubbles. A process embody ing this invention may involve the use of these agents and a simple preliminary test of any particular ore would determine the chemical constitution of the solution to be employed. In most of the experiments which led to the present'invention the pulp was alkaline containing about 0.1 to 0.3% of sodium carbonate in solution. Successful results have also been obtained with other salts such as sodium bicarbonate and sodium sulfate.

With regard to sized material, this inventionv is particularly applicable to finely crushed mixed sulfid ores of the following sizes: (80 +100), (-100 +120), or 120 +150), these sizes being given in meshes to the linear inch according to the standard of the Institute of Mining and Metallurgy. The more closelysized the product'is, the more exact is the selective flotation.

The following examples illustrate the application of this invention. -In each case the test was made in a small laboratory apparatus of the general type described in my United States Patent No. 1,155,816, issued October 5, 1915.

Ea'ample 1.

The crude ore was crushed and sized and the particular s'ze in this test was 120 150 I. The original assay showed Zn 11.31%, Pb 11.76%. This material was treated in a circuit containing 0.11% of dry sodium carbonate (Na OO There was first added 2.7 ozs. eucalyptus oil per ton of ore and the mixture was agitated 4 minutes and one part of the first concentrates I was removed. There was then added 2.7 ozs. eucalyptus per ton of ore and the mixture was agitated for 4 minutes more and the second part of the first concentrates removed. There was then added 5. 1 ozs. eucalyptus per ton of ore and the mixture was agitated for 8 minutes and the third part of the first concentrates removed. It was observed that practically all the zinc had been removed. There was then added 3 ozs. per ton of ore of a mixture of Texas oil and wood tar oil, and the'mixture agitated for 3% minutes and the lead concentrate wasremoved.

The result of these four parts was as follows:

Proportion Asga y of g g g concentrate. Recovery 42 3 0 Zn 0 7n 4.5 7 0 4 7 Pb. J 1 2 2.4% Pb.

44.8% Zn. 87 Zn 9.5 2.6 Pb. U i I 2.1% Pb.

42.97 Zn. 6.7% 9.4 S Pb. 1.6% Ins.

6.2% Zn. 8 3 Z 1 L 5 2% gig; E' 86.8% Pb.

The proportion of tailings was 58.4, assaying 2.0% Zn, 0.6% Pb.

The first three parts form the zinc concentrate of average assay of 43.5% zincwith a recovery of 80.3% of the zinc.

E sample 2.

Here again the ore was crushed and sized and it was the size -120 +150 1. M. M.

that was treated in t is example, and the 3 original assay was 18.89% Zn 11.18% Pb.

The conditions were similar to those in Example 1,,except that the proportion of dry sodium carbonate was 0.176% on the water and the additions of eucalyptus were.

1.7 ozs. per'ton of ore for the zinc concentra'tes of which there were 2; and 3 ozs. of the mixture of Texas oil and wood tar oil for lead concentrate.

The results were as follows:

Proportion A of on inalin Ssay of Recover conce ntrate. wmentmte' y 47.3% Zn. 658 Z 26.3 4.67 Pb.

Lwzhm 8.5% Pb. 41.0% Zn. 3 10.0 7 10.07 Pb. 0 i 3.875 Ins. i 71% 4.1% Zn. 4 Z 19.4 60.07 Pb. l 11.5%; Ins. 822% The proportion of the original in the tail- 1ngs Was 4&2, assaying 3.3% Zn, 0.7% Pb. It will be clearly seen from these examples that in the case of the sized product the,

What I claim as my invention and desire to secure by Letters Patent is 1. A process of concentrating ores containing mixed metalliferous minerals which consists in sizing such an ore so as to obtain a plurality of products one of which is a graded product composed of particles of substantially the same size, and thereafter sub llferous mineral on the other hand, and sub-.

mitting the residue to further froth flotation treatment for the recovery of the metalliferous mineral contained therein.

3. A process of concentrating ores containing mixed metalliferous minerals which consists in sizing such an ore in a finely crushed condition into a plurality of grades each composed of particles of substantially the same size, and thereafter subjecting each grade separately to froth flotation treatment so as to preferentially float one of the metalliferous minerals.

4. A process of concentrating ores containing mixed metalliferous minerals which consists in sizing such an ore in a finely crushed condition into a plurality of grades each composed of particles of substantially the same size, and thereafter subjecting each grade separately to froth flotation treatment so as to obtain flotation products relatively high in a certain metalliferous mineral on the one hand and residues relatively high in another metalliferous min eral on the other hand, and submitting the residues to further froth flotation treatment for the recovery of the metalliferous mineral contained therein.

5. A process of concentrating ores contalning mixed metalliferous minerals which consists in sizing such an ore so as to obtain a plurality of products one of which is a graded product composed of particles of substantially the same size, and thereafter subjecting such graded product to froth flotation treatment with subaeration so as to preferentially float one of the metalliferous minerals.

6. A process of concentrating ores contaming mixed metalliferous minerals which consists in sizing such an ore so as to obtain a plurality of products one of which is a graded product composed of particles of crushed condition into a substantially the same size, and thereafter subjecting such graded product to froth flotation treatment with subaeration so as to obtain a flotation product relatively high in a certain metalliferous mineral on the one hand and a residue relatively high inanother metalliferous mineral on the other hand, v ther froth flotation treatment for the recovery of the metalliferous mineral contained therein.

7. A process of concentrating ores containing mixed metalliferous minerals which consists in sizing such an ore in a finely crushed condition into a plurality of grades each composed of particles of substantially the same size, and thereafter subjecting each grade separately to froth flotation treatment With subaeration so as to preferentially float one of the metalliferous minerals.

8. A process of concentrating ores containing mixed metalliferous minerals which consists in sizing such an ore in a finel plurality of grades each composed ofparticles of substantially the same size, and thereafter subjecting each grade separately to ffi) with subaeration so products relatively high in a certain metalliferous mineral on the one hand and residues relatively high in another metalliferous mineral on the other hand, and submitting the residues to further froth flotation treatores which consists in sizing such an ore so as to obtain a plurality of products one of which is a graded roduct composed of parand submitting the residue to furv th flotation treatment v as to obtain flotation ticles of substantially the same size, and

thereafter subjecting such graded product to froth flotation treatment so as to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand, and submitting the residue to further froth flotation treatment for the recovery of the zinc contained therein. a

11. A process of concentrating zinc-lead ores which consistsin sizin a finely crushed condition 1nto a plurality of grades each composed of particles of substantially the same size, and thereafter subjecting each grade separately to froth flotation treatment so as such an ore in 7 to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand.

12. A process of concentrating zinc-lead ores which consists in sizing such an ore in a finely crushed condition into a plurality of grades each composed of particles of substantially the same size, and thereafter subjecting each grade separately to froth flotation treatment so as to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand, and submitting the residue to further froth flotation treatment for the recovery of the lead contained therein. 13. A process of concentrating zinc-lead ores which consists in sizing such an ore so as to obtain a plurality of products one of which is a graded product composed of particles of substantially the same size, and thereafter subjecting such graded product to froth flotation treatment with subaeration so as to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand.

14. A process of concentrating zinc-lead ores which consists in sizing such an ore so as to obtain a plurality of products one of which is a graded product composed of particles of substantially the same size, and thereafter subjecting such graded product to froth flotation treatment with subaeration so as to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand, and submitting the residue to further froth flotation treatment for the recovery of the zinc contained therein.

15. A process of concentrating zinc-lead ores which consists in sizing such an ore in raeaeee a finely crushed condition into a plurality of grades each composed of articles of substantially the same size, an thereafter subjecting each grade separately to froth flotation treatment with subaeration so as to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand.

16. A process of concentrating zinc-lead ores which consists in sizin such an ore in a finely crushed condition into a plurality of grades each composed of particles of substantially the same size, and thereafter subjecting each grade separately to froth flotation treatment with subaeration so as to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand, and submitting the residue to further froth flotation treatment for the recovery of the lead contained therein.

17 A process of concentrating zinc-lead ores which consists in sizing such an ore so as to obtain a plurality of products one of which is a graded product composed of particles of substantially the same size, and thereafter subjecting such graded product to froth flotation treatment with subaeration in the presence of a minute quantity of eucalyptus oil so as to obtain a flotation product relatively high in zinc on the one hand and a residue relatively high in lead on the other hand.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ARTHUR HOWARD HIGGINS.

WALTON, 

